Railway-traffic-controlling apparatus



' 1 .c. c. BUCHANAN 1,773,515

RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed Feb. '7, 1927 w J wg m I v R LNVENTOFQ'.

Patented Aug. 19, 1930s UNITED STAT ES PATENT OFFICE CHARLES C.BUCHANAN, OP WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE UNION i SWITCH &SIGNAL COMPANY, 01" SWISSVALE, PENNSYLVANIA, A CORPORATION 01PENNSYLVANIA BAILWAY-TBAFFIC-CONTROLLIN G APPARATUS Application filedFebruary 7, 1927, Serial No. 186,408. Renewed January 28, 1980.

My inventionrelates to railway trafiic controll ng apparatus, andparticularly to apparatus 0 of such variations a v I will describeoneform-of .railwaytrafiic controlling apparatus embodying my invention,and will then point outthe novel features thereof in'claims.

The accompanying drawing is a diagramustratmg one form of railwaytra-fiic controlling apparatus embodying my invention.

Referring to the drawing, the reference characters 1 and 1. designatesthe track rails of a stretch of railway track over which traflicnormally moves in the direction indieatedby the arrow. These rails aredivided, by means of insulated joints 2, into a plurality of successivetrack sections only one of which, AB is shown complete in the drawing.Train controlling current is supplied to the rails of this section froma suitable,

, source of energy such as an alternator G.

The current supplied to the track rails by this alternator may be of afrequency of the order of the usual commercial alternating current suchfor example as 60 cycles or 100 cycles per second.

The supply of current to the track rails s controlled by a coding devicedesignated 1n general by the reference character X and comprisin aplurality of rotatable cams each designate by the reference character Cwith a suitable distinguishing exponent. The cams C are driven at aconstant speed by a suitable motor M which is supplied with current fromthe alternator G. The cam C is provided with a plurality of swells 8spaced about its periphery and which swells suc cessively engage acontact 3 to periodically close the contact as the cam C is rotated. Insimilar manner the cams C and (J are pro vided with diiferent numbers ofswells 8 which control contacts 4 and 5, res ectively. One, terminal ofthe alternator is con stantly connected with rail 1 of section AB,

ay witha'lternatin cur-- rent which is periodicallyfvaried at di erent'frequencies, and governingf means on th e train selectively responsiveto the frequency and the other terminal of the alternator is connectedwith the rail 1 through one of the contacts 3, 4', or 5, depending upontrafiic conditions.

- It is manifest that the alternating current supplied to the rails ofthe trackway by alternator G is periodically varied at the frequency ofoperation of the contact of the device X that is interposed between thealternator and the track rail 1. The coding device X may be constructedto provide variations of an reasonable frequencies, but for purposes 0illustration, I will assume that the cams C are rotating at 20revolutions per minute, that cam C has 4 swells, that earn G has 6swells, and that cam C has 9 swells. The selection between the severalcontacts of the coding device X in accordance with trafiic conditionsmay be accomplished in any suitable manner, such, for example, as bymeans of.,a home relayH and a distant relay L. The circuits forcontrolling these two relays form no part of my present invention andare omitted from the drawing for the sake of simplicity. For presentpurposes it is sufficient to state that home relay H is normallyenergized but is de-energized when a train occupies the sectionimmediately to the right of point B. The distant relay L is alsonormally energized but is de-energized when a train occupies either thefirst or the second \Vith the apparatus thus far escribed, when relays Hand L are both energized so that front contact 66 of relay H and frontcontact 7-7 of relay L are closed, current from alternator G, whichcurrent I will assume to be 100 cycles per second, is supplied to thetrack rails over contact 5 operated by cam C. Under these conditions thealternating current supplied to the trackway is periodically varied at afrequency of 180 cycles per minute. Current supplied to the trackwayunder these condition, I will hereinafter term the proceed code. Whenrelay H is energized and relay L is de-energized, the closing of backcontact 7-7 of relay L includes contact 4 controlled by cam C in thetrackwa circuit and under these conditions the tracl way is suppliedwith 100 cycle curopposite direction.

.a frequency of 80 cycles per minute, which current I will call the slowcode.

The train indicated diagrammatically at V is provided with governingmeans which is responsive to the frequency of the periodic variations inthe 100 cycle current supplied to the trackway. In the presentembodiment of my invention the train is provided with two magnetizablecores 11 and 11 located in advance of the forward axle 10 and disposedininductiverelation to thetwotrack rails 1 and 1, respectively. Core 11is provided with a winding 12, and core 11 is provided with a winding12, the two windings 12 and 12 being connected in series in such mannerthat the voltages induced therein by train controlling current flowingin opposite directions in the track rails at an instant are additive.indings 12 and 12 are connected through an amplifier 13 and atransformer Q, with a polarized relay R. lVhen train controlling currentis being supplied to the trackway, pulsating energy is elivered to theprimary of transformer Q at the frequency of the periodic variations insuch trackway current. For each impulse of energy supplied totransformer Q, during the increases of such current, an impulse of onerelative polarity is supplied to relay R and during the decrease 'ofsuch current, an im ulse of the opposite relative polarity is supp redto the relay. The relay R is responsive to the relative polarity ofthecurrent supplied thereto and it follows that when the traincontrolling current supplied to the trackway is being periodicallyvaried, the relay R is operated to close its normal and reverse contact15-15 and 15-45" alternate ly at a frequency which corresponds to thefrequency of the variations of the traclrway current.

Associated with relay R is a transformer T comprising a primary 16 and asecondary 17. Direct current is supplied to the primary 16 oftransformer T from a suitable source of energy such as a battery D, andthe polarity of such current is periodically reversed in accordance withthe frequency at which relay R operates. As shown in the drawing, whenrelay R is energized in one direction to close contact 1515 currentflows from battery I) through the lower half of primary 16 in onedirectionfand when relay R is energized in the opposite direction,current flows from battery D, over contact 1515 of relay R, through theupper half of primary 16 in the It follows that when relay R is operatedintermittently, the current in primary 16 of. transformer T isperiodically reversed at the same frequency as the periodic variationsin the 100 cycle current supplied to the trackway. As a result of thisperiodic current in the primary of trans former T there is induced inthe secondary 17 an alternating electromotive force of a correspondingfrequency, which electromotive force is applied to a plurality ofdevices which are selectively responsive to the frequency of the currentsupplied thereto. As shown in the drawing a plurality of rectifiers,each designated by the reference character J with a suitabledistinguishing exponent, are connected in parallel with secondary 17.Rectifier J supplies energy to a relay K and rectifiers J and J 3 supplyenergy to rela 's K and Y The rectifier J is connected irectly withthesecondary 17, but the circuits for rectifiers J 2 and J each contain acondenser 19 and a reactor 18. The circuit which supplies energy torelay K is tuned to resonance at a frequency of 180 cycles per minuteand the circuit over which current 18 supplied to K is tuned toresonance at a frequency of 120 cycles per minute. Relays K and K areeach arranged to be energized only when transformer T is deliveringcurrent of the frequency to which the circuit associated with such relayis rtuned.

In expl: uing the operation of the apparatus as a whole, I will firstassume that re lays H and L are both energized as shown in the drawing,so that current is being supplied to the trackway over contact 5controlled by cam C The proceed code thus supplied to the trackwaycauses relay R to operate at a requency of 180 cycles per minute and anelectromotive force of the same frequency is induced in secondary 17 oftransformer T. The current supplied to relay K under these conditionsenergizes the relay, and since thecircuit for rectifier J 3 is tuned toresonance at the frequency of-t-he current now supplied to it, relay Kis also energized. The circuit including rectifier J 2 is detuned,however, at 180 cycles per minute, so that relay K is deenergized. Underthese conditions current flows from battery D over front contact 2424 ofrelay K back contact 25-25 of relay K and front contact 26-26 of relay Kto the lamp 20, thereby lighting this lamp to indicate proceed.

I will next assume that relay H is energizer but that relay L isde-energized as by the presence of a train in the second section to theright of point B. Under these conditions current is supplied to thetrack rails in accordance witlnthe caution code and relay R operates ata frequency of 120 cycles per minute. The current delivered by secondary17 of transformer T therefore energizes relay K as before, and relay Kis now energized because this relay is tuned to the frequency of thecurrent supplied thereto,

- gized, as by the presence of a train in the sec tion immediately tothe right of point B,- section A-B is supplied with current in ac-'cordance with the slow code and relay R operates at a frequency of 80cycles per-minute. At this frequency relays K and K are both detuned sothat these relays are de-energized, but relay K is energized Currenttherefore flows from battery D over front contact 2424 of relay K backcontact 25--,25 of relay K and back contact 26-36 of relay K to lamp 22,thereby displaying a slow indication on board the train.

If section A-B were occupied by a second train located between train Vand point B, train controlling current would be shunted away from trainV by the wheels and axles of such second train. As a result, relay Bwould be continuously de-energized. If, for this reason or for any otherreason, relay B should fail to operate intermittently, the supply ofenergy to all the rectifiers J would bediscontinued, and under suchconditions relays K would all be tie-energized. Current from battery I)would then flow over backcontact 24.-24 of relay K to lamp 23, therebylighting this lamp to indicate stop.

One feature of my invention is the provision of means for supplying thetrackway with alternating current of commercial frequency periodicallyvaried at comparatively low frequencies of the order from 60 to 180cycles per minute, together with train carried apparatus includingresonant electric circuits which are tuned directly to the frequenciesat which the trackway current is interrupted for selecting between thevarious codes.

In this application I have disclosed apparatus which utilizes only threedifferent codes, but it should be particularly pointed out that myinvention is not limited to this number of codes but that the equipmentcould be expanded to provide additional code frequencies and additionaltuned circuits on the train to select between such additionalfrequencies.

Although I have herein shown and de scribed only one form of railwaytraflic controlling apparatus embodying my invention, it is understoodthat various changes and modifications may be made therein within thescope of the appended claims without departing from-the spirit and scopeof my invention.

Having thus described my invention, what I claim is:

1. Railway traffic controlling apparatus comprising means for supplyingalternating current of commercial frequency to the track- -.way, meansfor periodically varying such current at 80, 120 or 180 cycles perminute according to trafiic conditions, a train carried transformer,means for supplying the pri mary of the transformer with periodiccurrent of the same frequency as the variations in the trackway current,a first rectifier connected directly with the secondary of the.transformer, a second rectifier connected with the secondary through acircuit tuned to resonance at 120 cycles per minute, a third rectifierconnected with the secondary through a circuit tuned to resonance at 180cycles per minute, three relays, one connected with the output circuitof each rectifier, and governing mary of the transformer with periodiccurrent of the same frequency as the variations in the trackway current,a first rectifier con nected directly with the secondary of thetransformer, a second rectifier connected with the secondary through acircuit tuned to resonance at 120 cycles per minute, two relays, oneconnected with the output circuit of each rectifier, andcgoverning meansselectively controlled by the two relays.

3. Railway traffic controlling apparatus comprising means for supplyingthe trackway with alternating current of commercial frequency, means forperiodically varying such current, a train carried transformer, meansfor supplying the primary of the transformer with periodic current ofthe same frequency as the variations in the trackway current, a firstrectifier connected directly with the secondary of the transformer, aplurality of other rectifiers connected with the secondary throughcircuits tuned respectively to resonance at such frequencies, aplurality of relays, one connected with the output circuit

